Normotensive Patients with Primary Aldosteronism

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Clinical and biochemical characteristics of normotensive patients with primary aldosteronism: a comparison with hypertensive cases

Virginie Médeau*, François Moreau†, Ludovic Trinquart‡, Maud Clemessy§, Jean-Louis Wémeau, Marie Vantyghem, Pierre-François Plouin* and Yves Reznik†

*

Département d’Hypertension, AP-HP, Hôpital Européen s Pompidou, Paris, Service d’Endocrinologie et Maladies

Métaboliques, CHRU Côte de Nacre, Caen, Centre d’Investigations Epidémiologiques 4; Université Paris Descartes, Faculté de Médecine, Paris; INSERM Unité 36, Collège de France et INSERM U833, Paris; Service de Médecine Interne et Endocrinologie, Clinique Marc Linquette, CHRU Lille, France

Summary

Objective

It is unknown why some patients with biochemical evidence of primary aldosteronism (PA) do not develop hypertension. We aimed to compare clinical and biochemical characteristics of normotensive and hypertensive patients with PA.

Design and patients

Retrospective comparison of 10 normotensive and 168 hypertensive patients with PA for office or ambulatory blood pressure, serum potassium, plasma aldosterone and renin concentrations; the aldosterone : renin ratio, and tumour size. Comparison of initial hormonal pattern and drop in blood pressure following adrenalectomy in five normotensive and nine hypertensive patients matched for age, sex and body mass index.

Results

The 10 normotensive patients were women and presented with hypokalemia or an adrenal mass. Age, plasma aldosterone and renin concentrations were similar in normotensive and hypertensive cases, but kalemia and body mass index were significantly lower in the normotensive patients. Mean tumour diameter was larger in the normotensive patients than in the hypertensive matched patients with an adenoma ( P < 0·01). In normotensive patients, diastolic blood pressure and upright aldosterone correlated negatively with kalemia. Blood pressure was lowered similarly after adrenalectomy in five normotensive PA patients and in their matched hypertensive counterparts. Aldosterone synthase expression was detected in four out of five adrenal tumours.

Conclusions

Blood pressure may be normal in patients with welldocumented PA. The occurrence of hypokalemia, despite a normal blood pressure profile, suggests that protective mechanisms against hypertension are present in normotensive patients. (Received 17 August 2007; returned for revision 10 September 2007; finally revised 2 November 2007; accepted 3 December 2007)

Introduction

In the last 20 years, appropriate and accurate biochemical tools emerged for the large scale detection of primary aldosteronism (PA). 1 The clinical spectrum of PA now includes normokalemic hypertension which occurs in 60–90% of PA patients 1 but also unusual cases of normotensive PA revealed by hypokalemia or by an incidentally discovered adrenal mass. Seventeen reports, mostly including benign adrenocortical tumours 2–9 but also malignant tumours 10,11 have been published since the first description of normotensive PA in the 1970s. The mechanism(s) underlying the maintenance of normal systolic and diastolic blood pressure (BP) levels, despite an overproduction of aldosterone, are unknown. We compared the characteristics of 10 normotensive PA cases recorded over a 12-year period with those of hypertensive PA cases in a retrospective study. Our aim was to further define traits specific to normotensive patients in order to clarify the mechanism(s) for maintenance of normal BP.

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